Determinants of discrepancy between left ventricular chamber systolic performance and effective myocardial contractility in subjects with hypertension

Prognostic value of depressed midwall systolic function in cardiac light-chain amyloidosis

BACKGROUND

Cardiac amyloidosis represents an archetypal form of restrictive heart disease, characterized by profound diastolic dysfunction. As ejection fraction is preserved until the late stage of the disease, the majority of patients do fulfill the definition of diastolic heart failure, that is, heart failure with preserved ejection fraction (HFpEF). In another clinical model of HFpEF, that is, pressure-overload hypertrophy, depressed midwall fractional shortening (mFS) has been shown to be a powerful prognostic factor.

OBJECTIVE AND METHODS

To assess the potential prognostic role of mFS in cardiac light-chain amyloidosis with preserved ejection fraction, we enrolled 221 consecutive untreated patients, in whom a first diagnosis of cardiac light-chain amyloidosis was concluded between 2008 and 2010. HFpEF was present in 181 patients. Patients in whom cardiac involvement was excluded served as controls (n = 121). Prognosis was assessed after a median follow-up of 561 days.

RESULTS

When compared with light-chain amyloidosis patients without myocardial involvement, cardiac light-chain amyloidosis was characterized by increased wall thickness (P <0.001), reduced end-diastolic left ventricular volumes (P <0.001), and diastolic dysfunction (P <0.001). In patients with preserved ejection fraction, mFS was markedly depressed [10.6% (8.7-13.5) vs. 17.8% (15.9-19.5) P <0.001]. At multivariable analysis, mFS, troponin I, and NT-pro-brain natriuretic peptide were the only significant prognostic determinants (P <0.001), whereas other indices of diastolic (E/E' ratio, transmitral and pulmonary vein flow velocities) and systolic function (tissue Doppler systolic indices, ejection fraction), or the presence/absence of congestive heart failure did not enter the model.

CONCLUSION

In cardiac light-chain amyloidosis with normal ejection fraction, depressed circumferential mFS, a marker of myocardial contractile dysfunction, is a powerful predictor of survival.

Subclinical systolic dysfunction in pediatric patients with chronic kidney disease

OBJECTIVES

Midwall shortening (mwSF) is thought to be a more accurate measure of myocardial performance in the presence of left ventricular hypertrophy (LVH). We examined mwSF in pediatric patients with varying degrees of chronic kidney disease (CKD).

STUDY DESIGN

Fifty-seven children with CKD stages 2 to 4, 25 who were undergoing hemodialysis and 49 who were transplant recipients, were compared with 35 healthy control subjects. Left ventricular (LV) geometry and indices of LV function were assessed echocardiographically.

RESULTS

There were no significant differences in LV contractility or endocardial shortening fraction between patients and control subjects. Yet, patients undergoing hemodialysis had significantly lower mwSF compared with control subjects (P < .01) and patients with stage 2 to 4 CKD (P < .01). Renal transplant patients had lower mwSF compared with control subjects (P < .01). The prevalence of abnormal mwSF (ie, <16) was significantly higher in patients undergoing hemodialysis (40%) compared with patients who were renal transplant recipeints (12%) and patients with CKD stages 2 to 4 (9%; P = .03). With stepwise regression, mwSF was demonstrated to be predicted by using relative wall thickness (P < .0001), dialysis group (P = .005), and endocardial shortening fraction (P = .001; model R(2) = 0.86).

CONCLUSIONS

Children undergoing maintenance hemodialysis and children with concentric LVH have subclinical systolic dysfunction, which might be an indicator for the development of more severe cardiac disease.

Left ventricular longitudinal systolic dysfunction is an independent marker of cardiovascular risk in patients with hypertension

BACKGROUND

To explore the prognostic value of left ventricular (LV) longitudinal systolic dysfunction in patients with hypertension.

METHODS

In 156 hypertensive subjects, LV longitudinal systolic function was assessed by echocardiographic measurement of M-mode left atrioventricular plane displacement (AVPD) and Tissue Doppler (TD)-derived mitral annulus peak systolic velocity (Sm). Patients were followed for development of the following cardiovascular events: congestive heart failure requiring hospitalization, new-onset angina, nonfatal myocardial infarction, coronary revascularization procedures, transient ischemic attack, nonfatal stroke, and cardiovascular death.

RESULTS

Over a follow-up of 23.3 +/- 5.4 months, 24 patients had 29 events. Both longitudinal systolic indices were predictive of outcome (hazard ratios: AVPD, 0.24, P < 0.001; Sm, 0.22; P < 0.001). AVPD < or = 11.4 mm (75.0% sensitivity and 53.8% specificity) and Sm < or = 8.9 cm/s (79.2% sensitivity and 61.4% specificity) were identified as the best cutoffs for the prediction of cardiovascular events (area under curve: AVPD, 0.66, P < 0.01; Sm, 0.71; P < 0.0001). Compared to conventional indices of circumferential systolic function, AVPD and Sm showed similar overall diagnostic performance, but higher sensitivity and lower specificity. Coexistence of longitudinal and circumferential systolic dysfunction was associated with the worst prognosis (P < 0.0001). Multivariate analysis confirmed an independent association of longitudinal indices with clinical outcome, incremental to circumferential systolic impairment, and other confounding variables.

CONCLUSIONS

Longitudinal systolic dysfunction is an independent marker of cardiovascular risk in hypertensive patients. Despite similarity in predictive accuracy, longitudinal indices are more sensitive but less specific than circumferential indices for the prediction of cardiovascular events in these subjects.

Impact of obesity on left ventricular mass and function in subjects with chronic volume overload

OBJECTIVE

Previous studies evaluated the effect of obesity on left ventricular (LV) mass and systolic function in healthy subjects and in patients with coexistent chronic LV pressure overload due to hypertension, but no data exist regarding subjects with underlying volume overload. This study assessed the impact of overweight-obesity on LV mass and systolic function in patients with coexistent chronic LV volume overload.

RESEARCH METHODS AND PROCEDURES

In 885 subjects with degenerative aortic regurgitation, a common cause of LV volume overload, LV mass, ejection fraction, and myocardial contractility were determined by echocardiography.

RESULTS

LV mass was greater in overweight (193.5 +/- 54.2 g) and further increased in obese subjects (208.4 +/- 63.6 g) in comparison with normal-weight patients (177.7 +/- 54.9 g) (p < 0.0001), and these differences were still evident after adjustment for LV workload, gender, and body size. Despite no differences in ejection fraction, LV myocardial contractility was lower in overweight (92.6 +/- 14.8%) and obese subjects (91.7 +/- 14.4%) than normal-weight individuals (95.6 +/- 16.0%) (p = 0.0058). The magnitudes of these effects were not different from those found in age-, gender-, and body size-matched controls, suggesting additive interaction, rather than synergistic, between overweight-obesity and the underlying condition of volume overload. Multivariate analysis showed that BMI independently predicted LV mass and that the negative effect on LV myocardial contractility was mediated by LV hypertrophy.

DISCUSSION

Overweight and obesity are associated with LV hypertrophy and contractile impairment in patients with underlying chronic LV volume overload.